Would this be something possible? I can provide the actual effects set for cards like Whimsey from the microprose game.

My Christmas would be complete..

Had to do a bit of research there, never knew that the Dreamcast game had Astral-like cards made for it. Learn something new...

Generally we're only implementing cards which are Vintage legal. A line had to be drawn somewhere, and this way it fits with us not having the extra mechanics of Planechase, Archenemy and the impossible cards in the Un-Sets. Cards outside of Vintage never have their oracle text updated (Things like the recent 'create' wording for tokens), and are rarely errata'd.

Most of the cards dealing with random values could be done with groovy code, however the cards that deal with random effects wouldn't really work in Magarena, mainly in how the engine works.

It looks as though in the Microprose and Dreamcast games that each possible effect was programmed separately and assigned to cards which had them, allowing them to pull one out at random. Magarena builds effects 'on the fly' from card text or groovy files, so it would be near impossible to create random effects.

This does raise an issue with the ease of adding 'custom' cards - the scripts and files can be added, however there's one file in the engine that needs to be updated with the cardname. This isn't accesible in a normal install. ..magarena\resources\magic\data\AllCardNames.txt This allows the card to appear in the Card Explorer and Deck Editor windows. Raised as Issue #1005

edit: You don't need to edit any other files, putting the scripts in the scripts folder will enable them in game. They won't appear on any set filters however.

name=Shichifukujin Dragonimage=http://magiccards.info/scans/en/uqc/2.jpgvalue=2.500rarity=Rtype=Creaturesubtype=Dragoncost={6}{R}{R}{R}pt=0/0ability=SN enters the battlefield with seven +1/+1 counters on it.timing=mainoracle=Shichifukujin Dragon enters the battlefield with seven +1/+1 counters on it.\n{R}{R}{R}, Remove two +1/+1 counters from Shichifukujin Dragon: At the beginning of the next end step, put three +1/+1 counters on Shichifukujin Dragon. Activate this ability only any time you could cast a sorcery.requires_groovy_code

Ghastlord of Fugue and Shimian Specter both reveal the opponent's hand, the AI currently cannot use this extra information, so it would put the player at an advantage. These kind of cards won't be included until the AI can handle them correctly.

Evershrike is not currently able to be implemented due to the difficulty with how Aura targeting is implemented - It's a tricky one.